Means for inputting characters or commands into a computer

ABSTRACT

An apparatus and method for inputting a hand-generated character into a computer. A user draws a character using a drawing apparatus. As the user draws, movement of the apparatus and characteristics of such movement are detected. The apparatus generates a code for the character being drawn as a time dependent sequence of signals by comparing the characteristics of the movement as the character is drawn with a predetermined set of characteristics, with each signal corresponding to the predetermined characteristic closest to the actual characteristic detected at each successive step of movement. The apparatus provides visual feedback to the user by displaying in sequence each component of a character that is being drawn positionally independently of the movement of the drawing apparatus.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention concerns means for inputting characters or commands intoa computer or other information receiving device without a keyboard orthe like using the automatic skills of handwriting.

2. Description of the Related Art

The present day computer keyboard was initially designed to operate atypewriter. The keys were operated as levers to stamp a die onto paperto print each character. Each key carried two characters one above theother, the lower case character being reproduced by normal depression ofa key onto paper with an ink ribbon therebetween and the upper casecharacter being obtained by shifting the entire paper carriage or dieset so that the impact occurs with the upper character die impressionrather than the lower. Punctuation and special characters were obtainedby shifting the numbers or with extra keys.

The printing method is fundamentally the same as in a printing press butthe purpose of a typewriter is very different from the purpose of apress. Printing, of course, allows publication of a manuscript and thereproduction of many identical copies of the original manuscript withoutthe effort of handwriting each copy.

The typewriter came into being with the growth of modern commerce andthe need for legible business letters. At that time (and indeedpresently), handwriting was highly personal and showed great variation.from one person to another. This made handwritten letters, agreements,contracts and other legal documents potentially ambiguous or unclear inmeaning. It is this complexity of handwriting which mitigates againstcurrent approaches to computer analysis of handwriting.

Variations in handwriting represent simple information embedded in amass of redundant detail. In modern information and communications, theapproach to redundancy in a pattern is to throw large computing powerinto analysis and recognition. Computer equipment for analysinghandwriting is available but does require considerable computing powerand hence is relatively expensive and often cannot recognise thehandwriting quickly enough, in real time, causing delays to theinputting process.

The analysis employed in such methods depends upon the extraction ofsalient features from the pattern of handwriting presented to the deviceand its software. It should be noted that the salient features chosenare often complex and any one may be specific to one character orletter. This implies that the set of such features is large and complex.In addition there exists a number of different ways in which aparticular character can be drawn, each of which may contain differentsalient features. Add to this the difficulty that even with a single wayof drawing a particular character, the actual pattern drawn will varygreatly from one person to another. The result is that such approachesto the computer recognition of handwriting have so far been limited intheir success and often require a learning process in which the softwareadjusts to the handwriting of the user or the user learns a way ofwriting which allows the system to work. The overhead in terms ofprogramme size and computing power required is often expensive andimpractical in the application to hand-held computers or personaldigital assistants particularly at the smaller end of the scale of size,power and cost (the high volume market of pocket. databanks, diaries,organisers and the like).

Another approach to data input to a computer from finger movements isembodied in systems that require the user to draw each character in aparticular way, devoid of ambiguity. This results in a sort ofshort-hand code which has to be learned by the user. The short-handforms are often not familiar or readily recognisable as the charactersthey represent. The result is a commercially successful system but someway removed from natural writing and which needs to be learned andpractised.

Another difficulty associated with the current approaches to handwritteninput to a computer is the complexity and expense of the hardwarerequired for the sensing of the finger movements. In both the approachesdescribed above, the moment-by-moment and point-by-point form of themotion of the fingers must be sensed, digitised and transmitted to theprocessor carrying out the analysis and recognition. In many devicescurrently available this function is performed by a pen or stylus movedby the fingers across a touch sensitive screen. The finger motions aredetected by this device and transmitted to the processor, which causesan image of the movement to be displayed on the same screen. Such acomplex input device is expensive and can represent a significantproportion of the cost of for example a hand-held computer.

Thus, it is not easy to input hand generated information into a computerin a direct manner.

The printed word, on the other hand, is clear and unambiguous. Everycharacter can be standard in form and scale and easy to read. Theprinting press sets up its text as a block of lead type which isimpressed onto one or more paper pages at a time. This allows the rapidproduction of many copies of a page. The typewriter, however, needed tobe flexible at the level of each character, not at the level of eachpage. Hence, one key (one print operation) per character. Therefore, thepresent day keyboard has 60 to 70 keys.

Keyboards which deliver the component parts of each character (one partto one key) have been proposed. Because the form of printed numbers andletters can be simplified (they can be displayed with 7 and 14 segmentdisplays) such a keyboard would only need a relatively small number ofkeys compared to the standard keyboard. However, such keyboards have notbeen successful possibly due to the barrier of having to learn a new wayof typing which overrides the advantages of such a simple keyboard. Itis to be noted that during conventional touch-typing, although thefingers of both hands cover the keys, only one finger is working at atime. With character constructing keyboards as mentioned above, a numberof fingers must be employed simultaneously to print a character and soco-ordination skills must be learned by the user. This means that thetyping skill called for is less natural than the one-key one-characterscheme used by conventional keyboards.

SUMMARY OF THE INVENTION

An object of this invention is to provide means for inputting handgenerated information into a computer.

According to one aspect of the invention there is provided means forinputting a hand generated character into a computer comprising meansfor drawing a character, means for abstracting a sequence of signals asthe character is drawn corresponding to components of the character toproduce a code representative of that character and means forrecognising that code, whereby the character is inputted to thecomputer.

The signal abstracted preferably corresponds to a quantization of motionas the character is drawn. The signal abstracted may correspond to achange in direction as the character is drawn and/or may correspond tomovement beyond one or more defined thresholds in a particular directionas the character is drawn and/or a signal abstracted may correspond to achange in position of the drawing means from one defined area to anotherdefined are on a drawing surface.

According to a second aspect of the invention there is provided meansfor converting movement or force generated in reproducing a characterinto a coded signal corresponding to one or more elements of saidmovement or force that are indicative of the character, whereby thecharacter is recognisable from said coded signal.

According to a third aspect of the invention there is provided a devicefor converting movement of or force applied to at least a part of saiddevice, said movement or force being imparted by reproduction of acharacter, into a coded signal corresponding to one or more elements ofsaid movement or force that are indicative of the character, whereby thecharacter is recognisable from said coded signal.

According to a fourth aspect of the invention there is provided meansfor inputting a hand generated character into a computer having amonitor, comprising means for drawing a character to produce a sequenceof signals corresponding to that character, means for converting signalsproduced for one character into a code representative of that character,means for recognising that code and means for providing visual feedbackcorresponding to the character being inputted as the character is beingdrawn.

The means according to this aspect of the invention may be used with anyhandwriting recognition/input system whether involving quantisationrecognition or any other system of handwriting analysis.

According to a fifth aspect of the invention there is provided a visualfeedback to the writer on a display screen. Feedback may take the formof a sequential build-up or animation of a character form which itselfis produced from the above mentioned coded signal. Feedback may begenerated by the processor which is connected to the above mentionedinput means or input device or any other suitable input means.

Thus the display screen can show the results of the handwritingrecognition process as a feedback of information to guide the writer. Itpreferably operates step by step as the elements of movement are codedby the input device and includes the aspect of computer recognition inthe visual feedback process unlike all prior art. It does not indicatethe moment by moment movement of the fingers or the point by point formof the character as drawn, as is the case with current approaches tohandwriting input to a computer. The user is guided by theinterpretation of the finger movements by the system, so as to be ableeasily and naturally to produce just the correct finger movements thatwill code as the correct sequence of elements of unambiguous recognitionof the writing.

Preferably the visual feedback means comprises means for producing on amonitor a graphic simulation of a character component in response to anabstracted signal. The graphic simulation is preferably modifiable inresponse to a subsequent signal of a sequence for a character.

The graphic simulation preferably further includes an indicator as toposition of the drawing means on a drawing surface. The indicator maycomprise an icon displayed at or near an end of the latest graphicsimulation component. Alternatively, the indicator may comprise an iconthat moves around the graphic simulation of a character in response tomovement of the drawing means.

The feedback can be a smoothly produced animation of a cursive characterform that responds during its formation to the incoming flow ofrecognised elements or signal codes.

The computer or input device appears to the user to be cooperating inthe process of writing and to be producing the characters on the screenfrom the prompting provided by the finger movements.

Of course, the characters shown on the screen are not representative ofthe actual locus or form of the movement of the fingers, but aresynthetic representations of the intent of the user, and merely guidethe user in the inputting process. From the user's point of view thecharacters seem to appear as if written by the user, with thecooperation of the computer.

Such characters can build up to display a completed word, for example,in a standard, clear, joined-up cursive writing, each character of whichhas been produced from the sequence of simple elements produced by orabstracted from the operation of the input device.

When the user lifts the pen or signals the end of a word in anappropriate. manner, then the processor can immediately replace thecursive characters with the same word displayed in a selected fontappropriate to the application or application programme.

In contradistinction to prior art handwriting analysis systems whichinput information describing the character as drawn and carry out anextraction of salient features (necessarily scale and speedindependent), followed by comparison with a stored library of possibleshapes, strokes and their inter-relationships, both spatial andtemporal, to give the best fit to one character of a complete characterset, and thence to the recognised code for the character, the system ofthe present invention is a direct encoding system where the movementsgenerating the character as drawn, are compared with a single templatein such a way that complacent movements directly produce the elements ofa code that identifies the character completely by the time thecharacter is completed. At the instant the character is completed, therecognisable code has been completely built and no further analysis orprocessing is required for recognition.

Preferably recognition occurs character by character in real time. Theone or more elements of movement or force are preferably unit vectors.

Preferably analysis of movements or forces into elements is by means ofquantizing said movements or forces into one or a sequence of unitvectors. These elements are preferably speed independent, are preferablyscale independent and are preferably substantially independent ofdistortions or variations in the character as reproduced.

Preferably the elements form a set common to all the characters to bereproduced, which set does not contain elements specific to only one ora few characters.

The signal is preferably recognisable by a computer or any otherinformation handling device to which the device is connected, wherebythe character can be displayed on a visual display unit operated by thecomputer or can be processed in the same manner as a character inputfrom a keyboard.

If an input device were activated by movements similar to those employedin writing, then this could provide a method of inputting characters andtext into a computer without the need to learn a completely new skill.

What is here described is a device providing a method of analysis whichis mechanical or automatic and does not require an indirect process ofanalysis and comparison to produce a unique code for a character, incontrast to prior art.

This automatic generation of a unique character code may be facilitatedby means of a visual feedback from a display of the recognised elementsof a character as synthesised from the signal from the input device.

The automatic switch-like method of extracting the coded signal from thefinger movements gives rise to relatively simple and inexpensive inputdevices, recognition contemporaneous with the completion of ahandwritten character, low computing power requirement, naturalcharacter forms and ease of learning and use, in contrast to prior art.

Thus the invention herein described allows data input to a computer orother system by means of the natural finger movements employed inwriting utilising simple and low cost input devices with high speedrecognition and visual feedback.

There is an advantage to detecting motion as it is happening as opposedto analysing the space pattern of completed handwriting. The motion of apen when writing the circle of the letter “a” is different from themotion when writing the circle of the letter “p”, although the resultingshapes are very similar. The “a” circle is normally produced by ananti-clockwise motion whilst the “p” circle is normally made with aclockwise motion. This distinction is lost if the resultant handwrittencharacter is considered after it has been written. However, if thehandwriting is analysed dynamically, as it is being written, then theinformation gained is far more useful. It will be appreciated thatreferences to detection of movement include detection of applied forcesin generating said movements.

In a preferred embodiment the drawing means will be a hand held pen orthe like, whereby the pen or a part thereof can be moved to reproducecharacters.

It is envisaged that the drawing means of the invention will have a partthat may be moved relative to a real or notional template when acharacter is being reproduced and that the drawing means will includemeans for detecting said movement relative to the template. The templatemay be incorporated in the drawing means itself or may be separatetherefrom. There are various ways in which the movement of said part ofthe drawing means may be detected.

For example it may be possible to have a template around which said partof the drawing means can be moved, whereby contact of that part of thedrawing means on a sensor in a particular part of the template willindicate a direction of movement and again one movement or a sequence ofmovements will generate a signal corresponding to the character beingreproduced by those movements.

Put another way assuming a pen having a body, writing tip and a realtemplate, the template may be separate from the pen, such as on asurface, may be fixed to the pen body or may be fixed to the tip. On theother hand, for a pen having a body and a writing tip, movement ofeither or both may be relative to a notional template associated withthe body, the tip or a separate surface.

The means for detecting a movement of the drawing means or that partthereof may include contact switches, magnetic or capacitive sensors,optical encoders, light detectors, voltage changes, piezo-electriccrystal activation or any other suitable means.

The system of the invention preferably includes means for signallingcompletion of a drawn character. Completion may be signalled by liftingthe drawing means from a drawing surface. Alternatively, completion of acharacter may be indicated by a unique movement of the drawing meansrelative to that character. Another alternative may be to indicatecompletion of a character by movement of one of the drawing means and anicon indicative of the drawing means to a defined position, possibly onthe drawing surface or an area defined on a monitor.

The mode of analysis envisaged by the invention is actually concernedwith the time patterns of muscle action, in contrast to the spacepatterns of completed handwriting. It is relevant to note that allcommunication occurs through the medium of muscle action, whetherspeech, body language, touch, action, handwriting or typing. The firstoutward expression of thought is always through muscular action. Thisinvention is aimed at allowing the communication with a computer to takeplace at the level of the neuromuscular skill of writing.

It will be appreciated, however, that there is considerable redundancypresent in handwriting. Although handwriting may be taught in a uniformfashion, variations and embellishments are added as a person developshis handwriting skill, so that whilst letters and words can berecognised, it is extremely difficult for, for example, a computerscanning device to extract the essential characters because of personalvariations and embellishments.

Accordingly, a preferred aim of the device of the invention is to enablecharacters to be reproduced as unit vectors. In other words, eachcharacter as it is drawn using the device of the invention preferablyproduces a signal for that character as one or a sequence of steps. Thismay be achieved by limiting or restricting registration of the movementto one or a series of quantized steps or unit vectors.

It is important to realise that signals which solely describe theposition, movement or locus of a pen or moving part of the device simplyprovide a copy of that movement etc. in electronic, electrical etc form.They do not of themselves facilitate logical recognition of the inputtedletter form or character form.

What this invention allows is an automatic reduction of the movement etcinto a quantized form. This means that the movement is divided intosteps which indicate the time sequence of unit vectors whichcharacterise the movement etc. The steps themselves do not describe thepoint by point and moment by moment movement which results from drawingthe character form. They are rather the result of an analysis of themovement etc which indicates a series of unit vectors. This series ofunit vectors cannot be used to reconstruct the original fingermovements, because all redundant space and time information is discardedin the process of detecting the unit vector sequence. All that remainsis the sequence of the unit vectors and the character of the unitvectors.

The character of the unit vectors will be dependent on the design of thedevice. In the case of a physical square template the unit vectors couldbe characterised for example as being up, down, left or right.

The time delay between one unit vector and the next is not of importanceand is discarded information. All that matters for recognition is thesequence, eg. left then down then right then up then down for thehandwritten letter form “a”.

Also the process of deriving the unit vectors disregards the scale orsize of the movement or letter form. The same sequence of the same unitvectors results from a large “a” as from a small “a”. In addition,provided the physical movements which activate the movement or positiondetectors are smaller than the smallest character to be drawn, thesequence of unit vectors will be the same for wide variations ordistortions in the form of the original character, letter or resultingmotion.

It should be noted that such a family of unit vectors (one simple casebeing: UP, DOWN, LEFT, RIGHT) can represent all the characters to heinput to a computer etc through finger movements.

In other words, each and every number, letter etc can be analysed into asequence of the same set or family of unit vectors. The uniqueness ofcharacter resides in the sequence of the unit vectors which represents aunique code for the character. The different characters do not requireanalysis into unique individual features as in the prior art.

The analysis of original motion into unit vectors is according to ascheme which compares the movement to an arrangement of detectors placedin a fixed relation to a real or notional template. This allows themotion to be compared with the geometry of a template in such a way thata complacent movement will result in a single signal or part of a signalwhich indicates the characteristic direction or movement at that stageof the drawing of the letter or character etc.

For example, once the moving part has gone beyond the upper limit ofdetection, the unit vector will indicate simply “up” until the movingpart has once again returned within the scope of detection in thedirection, when it could be followed by “down”. Similarly withhorizontal movement. This approach leads naturally to a description ofoperation of the device in terms of a template.

The template is simply the geometry which determines the signalling ofthe unit vectors, and may be a physical form eg. a square aperturewithin which the pen tip etc. moves, or it may be notional, and issimply the space pattern of detector switching limits in two dimensionsor it may be embodied in the movement analysing processor which isconnected to the input device moved by the fingers.

Either scheme will result in practical devices which convert the fingerand hand movement familiar to us as handwriting into a code signalswhich is logically recognisable as corresponding to the character drawn.

For accuracy of coding, and in order to remove the inaccuraciesintroduced by personal embellishments, the writer may be guided byvisual feedback from an image on a display screen, and can choosenatural character shapes which can be learned quickly and easily.

Thus the device allows “typing” or inputting or textual information intoa computer or other automatic text handler (eg. typewriter, portabledatabank or diary etc.) at handwriting speeds or faster, without theneed to learn the far more complicated skills of touch typing using aconventional keyboard.

The principle of operation is based on the quantization of motion, andis not to be confused with handwriting analysis which causes automaticrecognition of the form of normal personal handwriting (or even therecognition of a limited or defined or stylised set of character forms)by an analysis of its complex actual shape.

The aim of the template either real or notional is to register themovement of the device as unit vectors but not necessarily to restrictthe movement of the device to unit vector form, whereby a recognisablesignal corresponding to that character can be produced.

In preferred forms of the invention the relation between the templateand the part or parts of the device will be flexible, thereby freeingthe device from performing forced angular, rectangular or linearmovements. In other words, by introducing a flexible linkage betweenrelatively movable parts of the device or between a movable part of thedevice and the template, the device can follow both straight and curvedlines whilst those movements will be detected as straight line movementsor forces producing unit vectors.

Thus, the preferred device of the invention has the ability to detectmovements of at least a part thereof in producing a character as one ora sequence of unit vectors to produce a signal corresponding to thecharacter, even when the character is not reproduced in a formatconstrained by the geometry of the template.

The flexible linkage may take any suitable form. For example, when thetip of a pen device is to be movable relative to the body of the device,the flexible linkage may be provided by one or more elastic memberslinking the tip to the body.

Various considerations may be taken into account in deciding the natureof the real or notional template.

In one preferred embodiment, the template may be in the form of anenclosure having at spaced positions around its periphery means fordetecting movement of said device part from one point to another aroundthe periphery of the enclosure. The enclosure may be of any suitableshape but will preferably be a square or a circle. Preferably fourdetection positions will be provided at equidistant spacings.

The movable part of the device may be a rod or the like and its movementfrom one detection point to another may be by any suitable sensor means,such as already suggested above.

In another preferred embodiment, the template may be in the form of aconfined track around which the movable part of the device can travel,again with spaced detection points as in the first preferred embodiment.

In a yet further preferred embodiment, the template is notional ratherthan real and may be embodied in the processor running the requisitesoftware and the movable part of the device may be detectable as beingin accordance with a template. Thus, the device of this preferredembodiment of the invention will include means for registering themovement of said movable part as though it were following a template.Thus, the device may be arranged to produce output signals when movementof at least a part thereof exceeds a notional boundary of the notionaltemplate.

It will be appreciated that these signals indicate major changes indirection as compared to a template or set of directions or axes. It ispossible to derive the signals indicating the unit vectors as changes invelocity or other time derivatives as well as direction or position.Such a derivation is suited to the application of this invention toconventional computer pointing equipment.

For example the data stream from a computer pointing device such as amouse, trackball, pen and tablet etc indicates the relative position ofthe fingers moment by moment. If this data stream is analysed by acomputer or dedicated processor in such a manner that excursions of thefinger position are compared with a notional template, encoded in analgorithm stored within the computer or processor or its associatedmemory as a pattern of excursion limits in two dimensions, movementsbeyond these limits or complacent with the template boundaries cantrigger the generation of a sequence of signals, indicative of the unitvectors, which codes uniquely for the character drawn by the fingerswhich are moving the mouse, trackball, pen and tablet or other pointingdevice.

This invention will now be further described, by way of example only,with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows schematically a system for writing into a computer;

FIGS. 2A and 2B show a possible arrangement for a pen device of theinvention;

FIGS. 3A and 3B show possible movement of the pen body of FIG. 2 and theresulting sequence of unit vectors around the template;

FIG. 4 shows alternative forms of a letter, each of which can berepresented by the same sequence of constrained movements;

FIG. 5 shows another possible arrangement for a pen device of theinvention;

FIG. 6 shows a unit vector sequence resulting from forming a letter;

FIG. 7 shows a variety of forms of the same letter that may all producethe unit vector sequence illustrated in FIG. 6;

FIGS. 8A to D show schematically operation of a pen device utilisingfrictional forces between its tip and a surface;

FIGS. 9A and 9B show the correspondence of intended character, unitvector sequence and the animated cursive character form used in thevisual feedback;

FIGS. 10, 11 and 12 show yet another form of pen device according to theinvention;

FIGS. 13A and 14A are sectional views through a yet further form of pendevice according to the invention; and

FIGS. 13B and 14B are sections on lines AA and BB respectively of FIGS.13A and 14A.

FIG. 15 illustrates the principle of using a virtual template inrelation to a pen device according to the invention;

FIG. 16 shows a pocket databank with conventional keyboard;

FIG. 17 shows a pocket databank with a pen device of the invention;

FIG. 18 shows a flow chart illustrating the procedure of synthesising ananimated image to be displayed on a screen to provide visual feedback tothe writer; and

FIG. 19 shows the flow of information in such a system employing aninput device of the invention and a method of visual feedback describedherein;

FIG. 20 shows a letter “a” reproduced with an additional movement toindicate completion and start of the next letter;

FIG. 21 illustrates detection of double unit vectors;

FIG. 22 shows detection of double unit vectors in drawing a letter “g”;

FIG. 23 illustrates provision of an actual pen position icon as a letteris drawn;

FIG. 24 illustrates provision of a synthetic pen position icon as aletter is drawn;

FIG. 25 illustrates how letters may be drawn starting from the samepoint;

FIG. 26 shows use of guide lines to aid character input;

FIG. 27 illustrates visual feedback compared to actual movement of adrawing device;

FIG. 28 illustrates a display screen with special areas for signallingcompletion of a character; and

FIG. 29 illustrates visual feedback with modification as new unitvectors are detected.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIG. 1 of the accompanying drawings, there is shownschematically an embodiment of the invention.

A pen device 10 contains a template which constrains the movementsperformed automatically by the fingers during handwriting and abstractsfrom these movements the elements that allow computer recognition. Theresult will be a “pen” which senses the sequence of movement elements ineach character while allowing the user to feel as if he is writing in anear-normal way. The sequence of movements can be registeredelectronically via mechanical switches or optical, electric or magneticsensors or other means and the sequences decoded by a microprocessor 12and the characters transmitted to a computer as if from a keyboard anddisplayed on a visual display unit of computer 14 as they arerecognised. Alternatively, the sequence can be transmitted directly forsimple logical recognition therein.

Taking this concept a step nearer to a practical form, one of thesimplest forms of template is a square and the template could beconstrained to move around the pen tip with the pen tip held stationary.Such a pen would feel like being forced to write in a squaredhandwriting. Add to this a “soft” or flexible linkage, integral with thepen, to allow for writing the circle of, for example, an “a” or a “p”.

Such an arrangement as shown in section in FIGS. 2A and B of theaccompanying drawings allows the pen to describe a circle while thetemplate moves around the pen tip in four segmented movements. As thepen body 18 is moved in a circle by the fingers, the flexible linkage 20will stretch to drag the template 24 around the pen tip 22. The forcesinvolved can be quite small—giving a slight tactile feedback to guidethe user. As the template is within the pen body, and is smaller thanthe smallest circle drawn by the user, the template will be pulledagainst the pen tip sides by the slight force of the stretched flexiblelinkage. The relative movement of the pen tip and template is,therefore, constrained to the four possible segments of the squaretemplate.

FIG. 2B shows the pen at rest and FIG. 2A shows the pen moved in thedirection of arrow F.

These segments can be thought of as “unit vectors” which can be one ofthe following: up down left right or u d l or r. Thus the sequence ofmovements for the “a” circle would be detected as:

l, d, r, u

and the sequence for the “p” circle will be”

r, d, l, u

FIGS. 3A and B show respectively how a letter might be drawn with thepen of FIG. 2 and the resultant sequence of unit vectors. This sequenceof unit vectors will be the same with a wide variation of circle shapessuch as shown in FIG. 4 of the accompanying drawings.

In FIG. 4, if all the circles were drawn clockwise starting with the pentip in the top right of the template then they would all produce thesame sequence of unit vectors:

d, l, u, r

and yet the user would feel that he was drawing a free form circle.

In a practical form of this pen the body would be moved by the fingerswhile the tip would be pressed onto a surface and held still. Thetemplate could then be integral with, and inside, the pen body (atypical template equivalent size is 0.5 mm per side) and the tip wouldsimply be the lower end of a spine rod that extended up the centralhollow of the pen, and connected to the pen body through the flexiblelinkage and thus be constrained to move around the sides of the squaretemplate. The user would feel that he was writing in a near normal waywhile the finger movements would be converted into a sequence of unitvectors.

It turns out that a square template, for example, can code uniquely forall the lower case letters of the English alphabet and for the numerals0-9.

In order for this device to be useful in producing movement sequencesrecognisable by a computer as characters, it is necessary to explore theunit vector conversion of each character in the character set a-Z and0-9. The character forms are desirably intuitive and simple. It isproposed to write in lower case and shift to upper case (for examplewith a simultaneous modifier key mounted on the pen body). A shift keycould allow the input of capital letters and the special characters ! @ú$ ˜& etc as with the standard keyboard. Thus, writing the character “a”while the shift key is down could give “A”.

Further modifier keys, for example “option”, could be employed togenerate commands to the computer.

It will be noted that many redundant codes of unit vectors are availablefor the special characters, punctuation and commands.

For example a single “left” movement giving the L unit vector coulddelete the last character input, with the same result as pressing the“delete” key on a computer keyboard.

To determine the start and end of each character a signal could begenerated by a switch inside the pen body activated by the pressure ofthe pen tip on the surface or by a third key. This key would be pressedwhile “writing” a character and released at the end of the charactersequence. The action becomes swift and automatic with a little practice.The end-signal would initiate the unit vector sequence analysis, alook-up algorithm lasting a few microseconds, and the character wouldthen appear on the computer screen.

In another embodiment of this invention, the character end can besignalled by a slight pause (for example while the visual feedbackdevice completes the animation of the intended cursive character form onthe display screen) and the end of a word is signalled by the writerlifting the pen from the “writing” surface.

An arrangement for a template is shown in FIG. 5 of the accompanyingdrawings. A square template 50 has sensor switches 52 (1, 2, 3 and 4) todetect the position of the pen tip 54 (more accurately the spine rod)within the square. These switches 52 are located at the centre of eachtemplate side and each switch operates whenever the spine rod ispressing against a particular side. It is the time sequence of theseswitch transitions that signals the motion of the pen relative to thespine rod and pen tip.

This leads to reduction in the redundancy of the information containedin the motion. Just as in the space domain the variation of form isremoved by reducing the motion into notional unit vectors (“unit”implying the transparency of the absolute vector length—only thedirection component is abstracted; this being effected by the design ofthe hardware switching), so in the time domain the variation in timingis removed by abstracting only the order of the switch transitions anddisregarding the absolute time intervals involved; this being effectedby the design of the software sequencing.

(Note that the spine rod and the template dimensions can be many timeslarger than the effective template size. The effective size is equal tothe possible movement of the spine rod or pen tip within the template.This can be typically 0.5 mm×0.5 mm. Compare this with the movementproducing a written “a” having a diameter of about 3 mm).

The sequence of transitions generated by drawing an “a” with thearrangement of FIG. 5 will be:

2−4+1−3+4−2+3−1+1−3+

(where + signifies a switch turning on and− signifies it turning off,the number preceding the sign indicating the switch number). This isbecause the unit vector sequence for “a” is: l, d, r, u, d starting atthe top right of the template (see FIG. 6).

Thus the same sequence of transitions will be generated if the userdraws the first curve of the “a” slowly and then speeds up or when hebegins quickly and then slows down. All that matters is the relativeorder of the unit vectors.

Also, provided that the miniature square template inside the pen issmaller than the smallest “a” drawn, all the “a”'s shown in FIG. 7 willalso encode as:

2−4+1−3+4−2+3−1+1−3+

irrespective of variations of form or scale.

Remember that the fingers move the pen body freely and the relativemovement of the tip and the template is effected through a flexiblelinkage. This means that the character drawn can contain curves yet thetemplate moves around the pen tip in a series of linear steps.

Turning to the question of stylising character forms to facilitaterecognition of movement sequences, it is to be remembered that the uppercase forms can be generated automatically by the look-up algorithm inresponse to the lower case unit vector sequence plus a shift key or thelike. It is important to realise that the locus of the pen body isinvisible. The pen movements are felt not seen. The pen does not“write”, it simply signals codes to the computer. The stylisedcharacters which may be used are virtual characters. The mind's eyeconstructs its own fond image of the character it thinks it is drawing.

Instead of the rigid finger positioning over the conventional keyboardduring touch typing, the pen allows a relaxed operation. As the pen doesnot need to move across the “page” and as the movements may be guidedautomatically by tactile and/or visual feedback there is absolutely noneed to look down at the pen.

One further embodiment of the invention is a pen device shownschematically in FIGS. 8A to D, wherein its tip 200 is held in contactwith a “writing” surface and is moved in relation to a real or virtualtemplate 202 by means of the frictional force between the tip and thesurface. This will signal the direction of movement of the pen body onit is moved by the fingers and hand. FIGS. 8A to D show respectively thepen moving downwards, upwards, to the left and to the right. As the tipmoved under frictional forces, it touches contacts 211, 212, 213 and 214respectively and thus signals a unit vector sequence. Such a pen is freeto move over a surface in the same manner as a conventional pen.

Referring to FIGS. 9A and 9B, these tables show character stylisationswhich form a character set which is only one example of many possiblesets. The optimum set in any particular embodiment of the invention willdepend on the template design and the arrangement and logic of theswitching and the relationship to the animation sequences chosen tooptimise the visual feedback as well as personal preferences.

This set relies on a flexible linkage to give a realistic feel to thedrawing of the letters. Obviously the simple square template will notallow excursions (tails) up or down. However the fingers carry these outautomatically, the pen body following the fingers, but the spine rodstays within the template square. Happily each character still generatesa unique unit vector sequence and codes unambiguously into the targetcomputer.

Obviously the writer will have to adapt the writing of each character toproduce just the unit vectors required for error free recognition.However the abundance of codes derivable from sequences of unit vectorsallows for multiple ways of drawing particular letters. (See the exampleof the letters “b” and “q” in the set of FIGS. 9A and 9B).

Most importantly the visual feedback will guide the writer effortlesslyif the elements of the animation building the cursive character formsare designed to confirm the completed movements at any point in time andprompt for the required subsequent movements.

Because of the flexible linkage and the mind's own image of what it istelling its fingers to do, these letter forms seem quite natural.

After a little practice, far less than is needed to become skilled atusing a conventional keyboard with all these characters, the componentmovements are not created individually but in a fast automatic flow, asthe mind goes through the act of writing each character. The speed canbe typically 20 unit vectors per second.

In FIGS. 10, 11 and 12 is shown a form of pen according to the inventionin which the pen has a body 60 which is movable relative to a template62 in the pen tip 64 which is held stationary upon a surface. The pentip 64 may include a suitably shaped rubber or the like pad which isrelatively non-slip upon say a table.

The advantage of this embodiment is that the actual movement of the penaround the template and the imagined movement of the pen tip areequivalent. With the pen described earlier, these movements are oppositein sense and the mental link between the two has to be unlearned. Thetemplate may be of any desired shape with movement sensors also of anydesired type as described hereinbefore or later.

Another refinement, which may be applicable to four-switch templates andmore complex templates, is to generate the character start and endsignals from the template switches. The start signal may be turned onwhenever at least one of the template switches is on, and may be turnedoff whenever all four template switches are off. This defines a startingpoint for the pen tip at the centre of the template. If in addition, thepen tip is centre-sprung, ie. automatically returns to centre after eachexcursion, either by slightly lifting the pen or simply by relaxingpressure, then the process of sending a character becomes easier andautomatic. The logic of the start signal may be handled electronically.

More complicated templates can be constructed, where the freedom ofmovement of the pen tip is greater. An analogy would be the increasingcomplexity of car gearshaft gates as the number of gears increases.

When a physical or real template is being used, the effective size ofthe square template may be reduced until the relative movement of thepen body and the spine rod or pen tip is arbitrarily small. The unitvectors may then be sensed using pressure transducers or strain gaugeson each of the four template sides.

Character start/stop signals can be derived logically from the templatesignals.

A degree of flexible linkage is desirable to allow a very slightmovement of the pen under the pressure of the writing fingers. This canbe achieved by moulding the pen tip from say rubber or like material,and/or building in a slight compression movement into the pressuretransducers or some other convenient position.

The movement of the pen in this arrangement is not constrained soobviously to a square template, however the signals from the transducerswill conform to the same coding sequences for the same characters.

Writing control can be effected by means of an audible feedbackgenerated from the vector recognition circuits. For example, as thefingers go through the movements of a particular stylisation, an audiblesignal can be generated as each vector is completed, the frequency ofthe sound being arranged to be unique to each vector. After a littlepractice this feedback could be muted or disabled. The occurrence of amistake (unrecognised sequence) for a particular character could switchthis feature back on for a predetermined number of characters following,thus reinforcing the learning process. Just as when, while dialling afamiliar number on a touch-tone telephone, a mistake immediately“sounds” wrong and familiar groups of numbers sound right.

A further feedback to facilitate both learning and the normal operationof the device could be a visual indication of the vectors themselves asthey build up to describe a character. Most computer displays operatingin word processing mode employ a cursor shape on screen to indicate theinsertion point. This could be replaced with say a square representationof a virtual template showing the vectors as emboldened sides of thesquare (or whichever alternative template shape is used). At characterend-signal this graphic would be replaced with the coded character andwould itself move on to the next text position, ready to display thenext pattern of vectors.

More sophisticated techniques of visual feedback and confirmation may beemployed, in which the vector sequence information is used to synthesizea graphic image on screen which reflects the growing character asintended by the operator, using a stored programme to determine theavailable possibilities at each stage in order to guide the formation ofthe inputted character.

Such a system of visual feedback is illustrated in FIG. 18 which is tobe read as a flowchart. Here the way in which characters that all beginwith an “UP” unit vector (chosen as an example) may be reproduced on adisplay screen as a progressively developing image of the intendedcharacter in synthesised, clear, standard, cursive form (represented inthe square boxes) is illustrated.

In the flowchart of FIG. 18, the sequence of unit vectors is indicatedby the symbols in the circles. Thus 1U indicates that the first unitvector is “UP”. Similarly, for example, 6L indicates that the sixth unitvector is “LEFT”.

At the point of recognition, when the system decodes the finger movementinto a unique unit vector sequence for a specific character, then at thecorresponding point in the flowchart of FIG. 18 the recognised characteris indicated by a square box containing the corresponding fontcharacter.

The progressive animation develops each character as the fingers move indrawing the character while holding the input device which convertsthese movements into a sequence of unit vectors. It is this stream ofunit vectors which determines the animation process. Thus the feedbackloop is closed allowing a completely novel method of inputtinghandwritten information into a computer or the like.

In other words the eye sees the character form on the screen as thefingers move in such a way as to produce the unit vector sequence. Thecomputer etc appears to cooperate with the user in the process ofwriting the characters.

In the example illustrated in FIG. 18 the letters “l” “h” “b” and “t”are reproduced and recognised. It can be seen from this example that allthe basic forms of the characters “a” to “z” and “0” to “9” can besimilarly analysed into unit vectors and animated on a display screen.

It is important to note that the definitions of the letter forms interms of the unit vectors bears a functional relationship to thesequence of metamorphosis of the animation of the synthetic on-screencursive character forms. As the unit vector sequence is generatedautomatically, the animation responds by developing the letter throughthe forms possible at each stage. Thus referring to FIG. 18 the letterform for a cursive l transforms into the cursive form for the letter hwith the further input of unit vectors U R D. Similarly the h transformsto the form b after an L unit vector. Thus, the design of the cursivefont employed in the visual feedback animation contains the structure ofthe basic handwriting movements as defined by the unit vector sequences(ie simple changes of average direction) as can be easily andautomatically detected.

Thus the design of the visual feedback font and the process of itsanimation is very important. It is envisaged that different such fontscan be designed for different applications, languages, countries andscripts and users.

This gives rise to a device which allows the writing of naturalcharacter forms to be elegantly guided by visual feedback, thus placingthe brain, fingers, input pen or input device, computer processor,display screen and eye, all in the same feedback loop.

FIG. 19 shows this feedback loop. The flow of information is indicatedby the arrows 406 (1 to 5). The fingers 400 of the writer perform themovements of writing a character and these movements are detected by theinput device 401 which automatically produces signals indicative of theunit vectors characterising the character drawn. These signals are fedto a processor 402 which synthesises an animated image in response tothe sequence of these unit vectors. The animated character is displayedon a display screen 403 and viewed by the eye 404 of the writer. Thusthe brain 405 of the writer receives feedback according to thedevelopment of the unit vector sequence in terms of the development ofthe synthesised image indicative of the writer's intention, and is ableinstinctively to correct the movement of the fingers to cause correctcomputer recognition of the character drawn.

The process of computer recognition is thus included in the totalfeedback loop involving the user. This is in complete contradistinctionto prior art, where the feedback is merely from the reproduction of theactual finger movements on the display screen and does not include therecognition process itself.

The end of each character is signalled in this example by a slight pausein pen movement, shown in FIG. 18 as a letter P in a circle. However,the on-screen animation can produce joined-up cursive handwriting by asimple process of stored instructions responding to the unit vectorsequence, and animating the connecting links between letters.

It should be noted that the process of animation can present the userwith a continuously moving cursive line on the display screen, inresponse to the signals from the input device, which may themselves bediscontinuous in time. The eye sees what the mind intends, rather thanwhat the fingers are doing. After a very short period of use, theprocess can become virtually automatic and natural.

At the end of each word the pen or input device may be lifted up just asin normal writing onto paper) to activate a signal (producedautomatically from a switch or other sensing means) to the systemprocessor to initiate the transformation of the completed cursive imageof the written word on the screen into the corresponding font charactersof the application programme etc which is the object of the data input.

It should be noted that each character is recognised at the pause afterthe last unit vector has been input. In other words the user will pausemomentarily after completing each character, while the processorcompletes the animation of the cursive character form on the displayscreen. This image of a cursive character form is already a product ofthe recognition process and has been derived from a unique code of unitvectors already input to the system, and should not be confused with thecursive forms indicative of the actual unrecognised finger movementsdisplayed in inventions of prior art.

In this example the cursive form is displayed on screen until the wholeword is completed to facilitate useful feedback to the writer.

It should be understood that the cursive letter form so synthesised anddisplayed bears a functional relationship to the finger movementsemployed in writing the character. It would not be so useful to displaythe “printed” font characters at this point.

The structure of the synthesised character forms is based on the unitvectors that characterise the corresponding written characters. Thisrelationship can be seen in the example of the flowchart of FIG. 18.

The feedback thus guides the writer in a most natural way to input thecorrect sequence of unit vectors, without consciously having to payattention to that level of analysis.

Once the whole word is completed the system has all the informationrequired to display the recognised characters in the final form of“printed” font characters to make up the complete printed word.

It is easy to conceive computer learning programmes to take a new userthrough the structure of the character set stylisations, using graphicsand feedbacks similar to those described above.

It is possible to use a virtual template as opposed to a physicaltemplate. The character recognition in the physical template systems isfacilitated by the simplification of the movement by means of thephysical boundary of the template and by the resultant reduction of thatmovement to scale-independent and speed-independent unit vectorsequences.

However, a further refinement is still possible, in which therestriction of the movement by a physical barrier is replaced by anotional limit to the registration of that movement. If movements areonly recognised by sensors in directions parallel to the sides of anotional, non-physical template, and if these movements are quantized bythe sensors and/or their associated electronics and algorithms up to aspecific limit of excursion, and if this limit is smaller than thesmallest character drawn, then the end result will be the same for thesame character stylisations as with a physical template.

This would lead to the design of physically simpler, faster pens ortouch screen sensing of stylus or finger movements and allow theinvention to work utilising the input devices now available forcomputers such as the mouse, tracker ball, finger pad, touch sensitivescreen, pressure sensitive screen, pen and digitising tablet and thelike.

Further refinements of the invention are described below with referenceto FIGS. 20 to 29 of the accompanying drawings.

Characters to be input are defined in terms of the movements required toproduce the appropriate unit vector sequence. Therefore, predeterminedstyles of character are pre-supposed. These characters can be very closeand in most cases identical to natural character forms. Characters maybe defined in terms of unit vectors in such a way that each character isrepresented by a unit vector sequence that is not a truncation of anylonger unit vector sequence for another character. That can allowcontinuous input (eg within a word without necessarily signalling insome way completion of a character. Thus, completion of a character maybe signalled by the last unit vector of the defined sequence for thatcharacter.

An example of such a unit vector set follows:

a=rldrud then r for start

b=uddurdl then r for start

c=rldr then r for start

d=rldruudd then r for start

e=ruldr then r for start or ruld then r for start

f=uddu then rr for start

g=rldruddl then r for start

h=uddurd then r for start

i=d then r for start

j=dl then r for start

k=uddrl then r for start

l=udd then r for start

m=dudud then r for start

n=dud then r for start

o=rldru then r for start

p=dduurdl then r for start

q=rldudd then r for start

r=duudr then r for start

s=rudl then r for start

t=udrld then r for start

u=drud then r for start or dru then r

v=du then r for start

w=dudu then r for start

x=rl then r for start

y=druddl then r for start

z=rlrdl then r for start

FIG. 20 shows an animated screen image corresponding to movement of adrawing device in drawing a letter “a” according to the above unitvector set. The last RIGHT movement signals the completion of a uniqueunembedded code for “a” and therefore the end of the character. That canbe used to cause the visual animation on the display screen of a lineextending to a standard start position for the next character.

The signalling of the end of a word may be achieved by pen liftactivating a switch or sensor or other eg button press, or a specialunit vector sequence or special movement sequence.

Unit vectors may be derived in the following ways:

from switches detecting motion in a pen device as described above;

from exceeding a threshold of motion in a direction;

from exceeding a threshold of any combination of time derivatives ofmotion in a direction;

from movement from one defined area of writing surface to another;

from substantial complacency with a direction or axis or template side;

from combinations of the above.

Here substantial complacency means that the resolved vector componentsof the motion parallel to the direction, axis or template side aregreater than those parallel to all other defined directions, axes ortemplate sides in the system.

To facilitate drawing and recognition of some characters, it may beuseful to be able to detect doubling of unit vectors. In other words indrawing some characters unit vectors may repeat one after the other.Detection of two vectors in the same direction may be detected byarranging two detectors with different thresholds of detection or twotemplates (real or virtual) one after the other so that the movementproduces the detection of first one and then the second unit vector inthe same direction. This is illustrated in FIGS. 21 and 22 of thedrawings. In FIG. 21 the arrow indicates the direction of movement ofthe drawing device or pointer. FIG. 22 shows how this can be used, forexample, for the letter “g”.

Pen and pointer devices used in conjunction with computers andassociated display screens or monitors often employ the reproduction onthe screen of a line of pixels that represents the track or locus of thedrawing device. This is some times termed “screen ink”. Such a displaycan be used in conjunction with unit vector detection to guide the userin forming the correct letter shapes.

Referring to FIG. 23 of the drawings, it is possible to cause an icon ona monitor screen to move in response to the actual movement of thedrawing device. The icon 500 can be used to appear adjacent to theanimated font providing visual feedback as described above. This allowsthe user to judge more accurately the movements required to causecorrect unit vector recognition, as confirmed by the display of thecorresponding animated font elements 501, 502, 503, 504, for example,corresponding to the input of a drawn letter “o”.

As the pointing device is moved to produce the display of animated fontelements on the monitor screen, it is advantageous to indicate thedirection of pen movement and to give a simulacrum of the pen positionby causing the processor controlling the monitor to display an icon atthe end of each consecutive animated font element. This icon is not tobe confused with the icon which responds to and represents the actualdrawing device movement. FIG. 24 of the drawings illustrates thesequence of images that result from the input of the letter “o”. Icon520 appears at the end of each animated font element 521, 522, 523 and524 as the letter “o” is input.

It is advantageous to arrange the drawing of characters so that they allstart from the same point. This allows the writer to memorise one set ofcharacter forms which do not need mental re-adjustment of the penposition before the input of the next character. This leads to increasedspeed of writing. FIG. 25 of the drawings shows examples of letters thatcan be drawn from a common start.

At the end of each character it is advantageous to arrange the visualfeedback to move the position of the pen position icon (whether actualor synthetic) from the end position of the character to the standardstart position. This immediately re-adjusts the writer's assumption ofpen position to facilitate the speedy input of the following character.

The same result may be obtained by advancing the screen ink to thestandard start position, or by causing the animation of a font elementon the monitor to bridge the gap between the end position and thefollowing standard start position. That is shown, for example, in FIG.20 of the drawings, where the final right unit vector signals completionof the character “a” and the visual feedback automatically produces aline extending to the common start position.

FIG. 26 illustrates provision of guide lines on a monitor display to aidcorrect input by providing indications of appropriate relative scale andnecessary movement in conjunction with screen ink or actual pen positionicon. This ensures a more regular drawing of characters and a scalewhich is consistent with the scale of the unit vector detectionthresholds.

The use of extending vector images to provide visual feedback is analternative way of guiding the user in the input of characters toproduce correct unit vector sequences. The unit vector detected causesthe image displayed of the pointing device movement to be locked to thecorresponding direction and allows the input of a line reproduced on thescreen that represents the extension of the movement. When the directionof movement changes sufficiently to trigger the recognition of a newunit vector, then the displayed line is locked in the new direction.This visual feedback allows simulacrum images of the intended charactershape to be displayed as straight line segments corresponding to thedegree of movement in each direction. FIG. 27 illustrates the method.

It is advantageous to use special areas or special guidelines on thedisplay screen used in conjunction with screen ink and/or pointer icon,in order to signal character end and therefore allow continuous input(eg within a word) without lifting the pen device or otherwise needingto signal character end and/or in order to signal control or modifiercharacters or signals. In this method when the pen position icon and/orscreen ink moves into an area of the monitor display surfacecorresponding to a defined area of the writing surface, or when the penenters the defined area of the writing surface, or when the pen crossesa defined line on either surface, a signal is produced by the processorwhich indicates the end of a character or other control event orcommand.

This allows the rapid input of joined-up cursive characters without theneed to lift the pen or otherwise signal the end of each character. Thisis shown in FIG. 28 of the drawings in which movement of screen ink orpen icon into shaded areas 550, signals the end of a character.

Visual feedback may include the modification of displayed characterelements as new unit vectors are detected. FIG. 29 of the drawingsillustrates this method. The seat of the “h” is modified into the circleof the “b” upon detection of the L (left) unit vector. Subsequently, thecircle of the “b” is modified into the curl of the “k” on detection ofthe final R (right) unit vector.

A practical drawing device for use in the invention, which has beenbuilt to prove the efficacy of quantisation of motion to produce unitvectors from the finger movements of handwriting, is now described withreference to FIGS. 13A and B and 14A and B of the accompanying drawings.It will be appreciated that many forms of pen can be produced in for usein this invention and that in addition existing computer input devicescan be adapted to embody the invention herein described.

These drawings show a pen 100 having a tubular body 102. Extendingthrough the lower end of the body is a rod 104 which is pivotallymounted in the body at 106, so that when the tip of the rod is heldstationary on a surface, the pen body can move relative to the tip indirections normal to each other. Within the pen body are four lightsources 108 each being at the mid-point of a side of a notional squaretemplate. Opposite each light source is an optical fibre 110 fordetecting an on or off situation for its own light source, wherebysignals can be generated for microprocessor recognition. The rod 104 hasa square shutter plate 112 on its upper end, which in a rest position,ie when the rod is centrally aligned with the axis of the pen, all ofthe light sources are detectable by their corresponding optical fibres110 but when the pen body is moved relative to the rod, the shutterplate is moved to obscure two of the light sources corresponding to thedirection in which the pen is moved. FIGS. 13B and 14B respectively showthe shutter in the neutral position and in position where the pen hasbeen pushed to the top right. The pen tip movement is constrained by asquare template 114 in the form of an aperture at the end of the penbody through which the pen tip extends. Thus, the pen includes the meansfor detecting direction of movement of the pen in forming characters inorder to generate a signal that can be recognised by a microprocessor orcomputer to produce the character on a computer screen.

If the pen tip has a built-in flexibility, the fingers can performcircular and curved movements while the signals are generated withreference to the square templates.

FIG. 15 of the drawings shows schematically a pen device operating witha virtual template. The position of the pen tip 150 relative to thecentre of the virtual template 152 is sensed in terms of its x, ycoordinates as shown. As the pen body is moved around the pen tip by thefingers, the notional template moves with the pen body and causes arelative movement between the pen tip and the template. The track orlocus of the pen tip relative to the virtual template is indicated byline 154.

The movement is referred to template sides, ie is registered as amapping of the pen tip position onto the template, resulting for examplein the unit vector L D R, which could decode as the character “c”.

Provided the pen tip travels around the outside of the template and thetemplate is always smaller than the smallest character drawn, then thesequence of unit vectors will always decode for the stylised charactershapes irrespective of the scale or speed they are drawn.

Another embodiment of the invention (see FIG. 17) consists of a templatebuilt in to a portable databank 300, or portable computer or otherproduct requiring the input of information such as a video recorder,pocket calculator, telephone, central heating controller, washingmachine etc etc. The template sensors are activated by the movement of asmall stylus 302 held by the fingers.

The stylus may be attached or hinged to the product or may be removableor separate. This application will allow the space taken up by datainput to greatly reduce as the stylus template 304 will replace the muchlarger keyboard or keypad 310 of a conventional pocket databank 312 (seeFIG. 16) having a screen 314. The stylus may fold down as shown toconserve space when not in use. The advantages of this embodiment of theinvention are that the product can be made considerably smaller, thestylus can be used with the eyes on the screen 314 and can be used moreeasily than the usually cramped keyboard keys, and data can be inputmore quickly. The input device can be fabricated at considerably lessexpense than a keyboard or touch sensitive screen. Also a data linkcable between the pocket databank etc could connect with a computer toallow text input from the built-in pen device to be input to thecomputer.

What is claimed is:
 1. Means for inputting a hand generated characterinto a digital device comprising means for drawing a character, meansfor detecting characteristics of movements in drawing a character toproduce a code for the character as a time dependent sequence ofsignals, by comparing each characteristic as the character is drawn witha predetermined set of characteristics, each signal corresponding to thepredetermined characteristic closest to the actual characteristicdetected at each successive step of movement, and visual feedback means,wherein a component of a character is displayed with each successivesignal in the sequence for the character being hand generatedpositionally independently of the drawing means.
 2. Means as claimed inclaim 1, wherein movement of the drawing means is abstracted as unitvectors.
 3. Means as claimed in claim 1, wherein recognition occurscharacter by character in real time.
 4. Means as claimed in claim 1further comprising means for displaying the recognized character. 5.Means as claimed in claim 1 further comprising means for providingvisual feedback corresponding to the character being inputted as eachsignal is abstracted.
 6. Means as claimed in claim 5, wherein the visualfeedback means comprises means for producing on a monitor a graphicsimulation of a character component in response to an abstracted signal.7. Means as claimed in claim 6, wherein said graphic simulation ismodifiable in response to a subsequent signal of a sequence for acharacter.
 8. Means as claimed in claim 6, wherein said graphicsimulation further comprises an indicator as to position of the drawingmeans on a drawing surface.
 9. Means as claimed in claim 8, wherein saidindicator comprises an icon displayed at or near the end of the latestgraphic simulation component.
 10. Means as claimed in claim 8, whereinsaid indicator comprises an icon that moves around the graphicsimulation of a character in response to movement of the drawing means.11. Means as claimed in claim 6 further comprising means for displayingon the monitor the character as a reproduction thereof.
 12. Means asclaimed in claim 1 including means for signaling completion of acharacter.
 13. Means as claimed in claim 12, wherein the drawing meansis arranged to signal completion of a character by lifting the drawingmeans from a drawing surface.
 14. Means as claimed in claim 13, whereincompletion of a character is indicated by a unique movement of thedrawing means relative to that character.
 15. Means as claimed in claim13, wherein completion of a character is indicated by movement of one ofthe drawing means and an icon indicative of the drawing means to adefined position.
 16. Means as claimed in claim 15, wherein said definedposition is an area of a drawing surface.
 17. Means as claimed in claim15, wherein said defined position is an area defined on a monitor. 18.Means as claimed in claim 1, wherein the drawing means comprises ahand-held pen-like device.
 19. Means as claimed in claim 18, wherein thedevice has a part, which is movable about a template during reproductionof a character.
 20. Means as claimed in claim 19, wherein the part ismovable relative to a notional template.
 21. Means as claimed in claim19, wherein the drawing means comprises a hollow body part movable abouta real or notional template within the hollow body part.
 22. Means asclaimed in claim 19, wherein at least one movable apart of the deviceand the remainder of the device and/or template are flexibly linked. 23.Means as claimed in claim 22, wherein at least one movable part of thedevice is a tip movable relative to a body of the device and one or moreflexible linkages affect movement of the tip relative to the body. 24.Means as claimed in claim 23, wherein the sensing means are selectedfrom electrical, photoelectric and magnetic sensing means.
 25. Means asclaimed in claims 19 including means for sensing direction of movementof said device or part thereof relative to a real or notional templatein reproducing a character.
 26. Means as claimed in claim 24, whereinsensing means are spaced about said real or notional template.
 27. Meansas claimed in claim 19, wherein the template is a generally squareenclosure.
 28. Means as claimed in claim 19, wherein the template is agenerally circular enclosure.
 29. Means as claimed in claim 19, whereinthe template defines a track.
 30. Means as claimed in claim 19, whereinthe template has a plurality of zones and said part moves from zone tozone in reproducing a character.
 31. Means as claimed in claim 1including means for converting a signal for a lower case character intoa signal for an upper case character.
 32. Means for inputting a handgenerated character into a digital device as claimed in claim 1, whereinthe characteristics of the movements in drawing a character aredirections of movement.
 33. Means as claimed in claim 32, whereinabstraction of a direction change is speed independent.
 34. Means asclaimed in claim 32, wherein abstraction of a direction change is scaleindependent.
 35. Means as claimed in claim 32, wherein abstraction of adirection change is substantially independent of distortions orvariations in the character as drawn.
 36. Means for inputting a handgenerated character into a digital device as claimed in claim 1, whereinthe characteristics of the movements in drawing a character aresuccessive positions.
 37. Means for inputting a hand generated characterinto a digital device as claimed in claim 1, wherein the characteristicsof the moverments in drawing a character are successive changes invelocity or higher time derivative of motion.
 38. Means for inputting ahand generated character into a digital device as claimed in claim 1,wherein the characteristics of the movements in drawing a character aresuccessive components of shape.
 39. Means for inputting a hand generatedcharacter into a digital device as claimed in claim 1, wherein thevisual feedback comprises display of a character built up and,optionally, modified step by step in correlation with the time dependentsequence of signals produced as the hand generated character is drawn.40. Means for inputting a hand generated character into a digital deviceas claimed in claim 1, wherein the visual feedback comprises automaticdisplaying of a character in a selected font being built up and,optionally, modified step by step, each step corresponding to one of thesignals of the code sequence for the character being drawn and in thesame order as the code sequence.
 41. Means for inputting a handgenerated character into a digital device as claimed in claim 1, whereinthe visual feedback comprises display of a character built up and,optionally, modified step by step in correlation with the time dependentsequence of signals produced as the hand generated character is drawn,and in that each step of the display is dependent on the precedingsignal or signal sequence of the character being drawn.